817806638712 has 128 divisors (see below), whose sum is σ = 2350765670400. Its totient is φ = 232244834688.

The previous prime is 817806638707. The next prime is 817806638713. The reversal of 817806638712 is 217836608718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (817806638713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24222339 + ... + 24256077.

It is an arithmetic number, because the mean of its divisors is an integer number (18365356800).

Almost surely, 2^817806638712 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 817806638712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1175382835200).

817806638712 is an abundant number, since it is smaller than the sum of its proper divisors (1532959031688).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

817806638712 is a wasteful number, since it uses less digits than its factorization.

817806638712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34625 (or 34621 counting only the distinct ones).

The product of its (nonzero) digits is 5419008, while the sum is 57.

The spelling of 817806638712 in words is "eight hundred seventeen billion, eight hundred six million, six hundred thirty-eight thousand, seven hundred twelve".